Thermotropic liquid crystal polymers for engineering applications

Collyer, A. A.

doi:10.1179/026708389790222474

Cited by 10 publications

(12 citation statements)

References 13 publications

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“…As a consequence of high molecular weight of an LCP, the number of LC phases through which a polymer passes is fewer than for an MLC. Often, only one LC phase exists for an LCP [70]. In contrast, the polymers in the present study showed a high-order smectic phase that includes SmB, SmE, SmF, SmG and SmI phases and low-order smectic phases (SmA or SmC).…”

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confidence: 55%

Main chain, thermotropic, liquid crystalline, hydrogen‐bonded polymers of 4,4′‐bipyridyl with 4,4′‐dicarboxy‐α,ω‐diphenoxyalkanes

Bhowmik

Wang²,

Han

2007

Liquid Crystals

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A series of main chain, thermotropic, liquid crystalline (LC) hydrogen-bonded polymers based on 4,49-bipyridyl as a hydrogen bond acceptor and 4,49-dicarboxy-a,v-diphenoxyalkanes as hydrogen bond donors were prepared by a slow evaporation technique from a pyridine solution and characterized for their thermotropic LC properties using a variety of experimental techniques. The homopolymer of 4,49-bipyridyl with 4,49-dicarboxy-1,9-diphenoxynonane exhibited relatively low T m at 205uC and low T i at 230uC, giving an LC phase range of 25uC. The other two homopolymers with 4,49-dicarboxy-1,6-diphenoxyhexane and 4,49-dicarboxy-1,9-diphenoxydecane exhibited relative low T m values, above which each of them formed highorder smectic phases. With further heating at higher temperature they transformed into loworder smectic phases that persisted up to their decomposition temperatures. Several copolymers also had relatively low T m values as well as low T i values and, therefore, had a broad LC phase range (22-77uC). All of the polymers including copolymers exhibited highorder and low-order smectic phases, since they developed usually mosaic and schlieren (or bâ tonnets) textures. Generally, copolymerization increased the temperature range of the LC phases for these polymers. The thermal transitions of all of the polymers were well below their decomposition temperatures, which were in the ranges of 254-329uC.

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confidence: 55%

Main chain, thermotropic, liquid crystalline, hydrogen‐bonded polymers of 4,4′‐bipyridyl with 4,4′‐dicarboxy‐α,ω‐diphenoxyalkanes

Bhowmik

Wang²,

Han

2007

Liquid Crystals

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“…In recent years the structure and properties of macromolecular mesophases have attracted a great deal of attention, which has been stimulated by the spinning of ultra‐high strength/high modulus fibers from nematic solutions of macromolecules with rigid backbones . Recently, anisotropic solutions have been obtained from solutions of semi‐rigid polymers such as cellulose and its derivatives .…”

Section: Introductionmentioning

confidence: 99%

“…In recent years the structure and properties of macromolecular mesophases have attracted a great deal of attention, which has been stimulated by the spinning of ultra-high strength/high modulus fibers from nematic solutions of macromolecules with rigid backbones. 1,2 Recently, anisotropic solutions have been obtained from solutions of semi-rigid polymers such as cellulose and its derivatives. [3][4][5][6][7][8][9][10][11][12][13][14] It is well known that the rheological properties of cellulose solutions greatly influence the spinning process, as well as the structure and properties of the obtained fiber.…”

Section: Introductionmentioning

confidence: 99%

Influence of water on phase transition and rheological behavior of cellulose/ionic liquid/water ternary systems

Lee

Kwon

Lee

et al. 2016

J of Applied Polymer Sci

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The influence of water content on liquid crystalline (LC) gel formation and the rheological behavior of a ternary microcrystalline cellulose (MCC)/1‐ehtyl‐3‐methylimidazolium acetate (EmimAc)/water system was investigated using polarized optical microscopy (POM) and rheometry. POM indicated that the distinct water content range for forming a fully anisotropic LC gel with 14 wt % MCC was 4–10 wt %. Adding water to the MCC/EmimAc system resulted in enhanced complex viscosity and storage and loss moduli, and ultimately LC gel formation. Comparison of creep compliance vs. time revealed that the system without water showed representative viscoelastic behavior, while the time dependence of creep compliance disappeared as the water content increased, suggesting elastic‐solid behavior. Additionally, hydrogen bonding between cellulose and EmimAc weakened as water content increased, whereas the intra‐ and intermolecular hydrogen bonds of cellulose became stronger because of strong self‐association. This strong bonding caused aggregation, chain entanglement, and self‐supporting LC gel network formation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44658.

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“…LCPs consist of repeating mesogenic monomer units that are incorporated into the main-chain of a polymer backbone. The incorporation of a rigid structure of mesogenic units to the main-chain polymer gives rise to an increase in melting temperature, high modulus and high strength [3]. There are two major LCP types: One is lyotropic LCP, e.g.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and properties of liquid crystalline polymers with low Tm and broad mesophase temperature ranges

Chen

Tsay

Chen

2005

Polymer

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Thermotropic liquid crystal polymers for engineering applications

Cited by 10 publications

References 13 publications

Main chain, thermotropic, liquid crystalline, hydrogen‐bonded polymers of 4,4′‐bipyridyl with 4,4′‐dicarboxy‐α,ω‐diphenoxyalkanes

Main chain, thermotropic, liquid crystalline, hydrogen‐bonded polymers of 4,4′‐bipyridyl with 4,4′‐dicarboxy‐α,ω‐diphenoxyalkanes

Influence of water on phase transition and rheological behavior of cellulose/ionic liquid/water ternary systems

Synthesis and properties of liquid crystalline polymers with low Tm and broad mesophase temperature ranges

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